Consider, if you please, the case of a passenger on a trans-Atlantic liner talking from his stateroom through the land line system of the United States to a regular subscriber's telephone on Catalina Island. This is entirely a possible task, and has been done in every technical detail. Here is the route: From the ocean liner telephone to a modulator, to an amplifier, to an oscillator, to the transmitting aerial on shipboard, through the ether to the receiving aerial on the Atlantic seaboard, to radio-frequency amplifiers, to a detector, to audio-frequency amplifiers, to the long distance line, to and through a series of repeaters in that line, each using a tube or tubes, to a modulator on the California coast, to an oscillator, to the transmitting aerial, through the ether to the receiving aerial on Catalina Island, to radio-frequency amplifiers, to detector, to audio-frequency amplifiers, to the local line and so to the receiving telephone.

And through all this maze of apparatus the voice current is repeatedly extinguished, then replaced by a similar- and frequently an augmented- copy of itself, coming out into the final telephone receiver in satisfying volume and quality.

RADIO for February, 1923